1. Field of the Invention
The present invention relates to a tube for packaging a processed meat such as ham and sausage and a method of packaging the processed meat.
2. Description of the Prior Arts
In a packaging of a processed meat such as ham and sausage, a ground meat is processed by seasoning, blending and ageing etc. to prepare a processed meat and the processed meat is filled in a tube of a film having high oxygen barrier property made of polyvinylidene chloride etc. and the processed meat filled in the tube is boiled at 80.degree. to 90.degree. C. for several minutes to several hours and quenched to prepare the product.
The film for packaging the processed meat should have high oxygen barrier property and should maintain a tightening modulus for pressing the inner processed meat (hereinafter the property for maintaining the tightening modulus is referred to as tightening property) even after the boiling and quenching step.
Heretofore, various films for packaging a processed meat have been developed. However, a film having both of satisfactory tightening property and satisfactory oxygen barrier property has not been commercialized and the development of such film has been needed.
The characteristics required for a processed meat packaging tube will be described in detail.
In an insertion of the processed meat into the tube, it is preferable to use a film having enough rigidity in order to improve a processibility for filling the processed meat into the tube. On the other hand, it is necessary to use a film having a strength to be durable under the weight of the processed meat and the pressure for filling the processed meat into the tube.
In the boiling step, it is necessary to use a tube having high shrinking property required for closely contacting and tightening the processed meat filled in the tube. Moreover, it is necessary to use a tube which is durable in the boiling treatment. The processed meat is expanded by the boiling treatment. It is necessary to use a tube having enough strength under the expanding pressure. It is also necessary to use a tube having high shape sustaining property so as to prevent excess elongation and a deformation caused by a softening.
In the quenching step, the boiled processed meat filled in the tube is dipped into a coolant water to quench it and then the product is usually stored at lower than 10.degree. C.
In the quenching operation, the processed meat is contracted.
When only the processed meat is contracted but the tube is not shrinked, a slack of the film is caused to deteriorate the appearance of the product and moreover, a liquid component of the processed meat is separated and filled in the cavities whereby the storage life is significantly lowered.
Thus, the tube should shrink depending upon the contraction of the processed meat and it should impart the tightening property for tightening the processed meat even at lower temperature.
Heretofore, it has been proposed to use a film made of rubber hydrochloride, polyvinylidene chloride. However, the rubber hydrochloride film has not enough oxygen barrier property and enough strength. The polyvinylidene chloride film has not enough rigidity and has low processibility and has not enough tube break resistance and shape sustaining property because of a decrease of strength in the boiling step.